1. Field of the Invention
This invention relates to optical components, and more particularly to circular polarizing filters.
2. Description of the Related Art
Optics systems used for precision imaging, measurement, analysis may employ circular polarizing filters to obtain a beam of circularly polarized light. A quarter wave plate may be placed after a linear polarizer to obtain such a circular polarizer, with a fast axis of the quarter wave plate aligned at a 45 degree angle from the polarizing axis of the linear polarizer to obtain accurate circular polarization.
As a practical matter, alignment of the fast axis of the quarter wave plate to the polarization axis of the linear polarizer is frustrated as the components become too small to physically handle and measure. Chip-scale optics modules that employ circular polarizing filters may require exact alignment of the relevant axes to properly interrogate a sample vapor in a chip-scale atomic clock, for example. The circular polarizing filter may then need subsequent alignment with a laser. Alignment tolerances for the quarter wave plate to the linear polarizer, and subsequent alignment of the components to a laser are frustrated by the difficulty associated with physically handling the very small components.
A need still exists to accurately align the fast axis of the quarter wave plate at a 45 degree angle from the polarizing axis of the linear polarizer for assembly into chip-scale optics systems without time-consuming placement and alignment of such small components.